1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/drivers/firmware/memmap.c 4 * Copyright (C) 2008 SUSE LINUX Products GmbH 5 * by Bernhard Walle <bernhard.walle@gmx.de> 6 */ 7 8 #include <linux/string.h> 9 #include <linux/firmware-map.h> 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/memblock.h> 14 #include <linux/slab.h> 15 #include <linux/mm.h> 16 17 /* 18 * Data types ------------------------------------------------------------------ 19 */ 20 21 /* 22 * Firmware map entry. Because firmware memory maps are flat and not 23 * hierarchical, it's ok to organise them in a linked list. No parent 24 * information is necessary as for the resource tree. 25 */ 26 struct firmware_map_entry { 27 /* 28 * start and end must be u64 rather than resource_size_t, because e820 29 * resources can lie at addresses above 4G. 30 */ 31 u64 start; /* start of the memory range */ 32 u64 end; /* end of the memory range (incl.) */ 33 const char *type; /* type of the memory range */ 34 struct list_head list; /* entry for the linked list */ 35 struct kobject kobj; /* kobject for each entry */ 36 }; 37 38 /* 39 * Forward declarations -------------------------------------------------------- 40 */ 41 static ssize_t memmap_attr_show(struct kobject *kobj, 42 struct attribute *attr, char *buf); 43 static ssize_t start_show(struct firmware_map_entry *entry, char *buf); 44 static ssize_t end_show(struct firmware_map_entry *entry, char *buf); 45 static ssize_t type_show(struct firmware_map_entry *entry, char *buf); 46 47 static struct firmware_map_entry * __meminit 48 firmware_map_find_entry(u64 start, u64 end, const char *type); 49 50 /* 51 * Static data ----------------------------------------------------------------- 52 */ 53 54 struct memmap_attribute { 55 struct attribute attr; 56 ssize_t (*show)(struct firmware_map_entry *entry, char *buf); 57 }; 58 59 static struct memmap_attribute memmap_start_attr = __ATTR_RO(start); 60 static struct memmap_attribute memmap_end_attr = __ATTR_RO(end); 61 static struct memmap_attribute memmap_type_attr = __ATTR_RO(type); 62 63 /* 64 * These are default attributes that are added for every memmap entry. 65 */ 66 static struct attribute *def_attrs[] = { 67 &memmap_start_attr.attr, 68 &memmap_end_attr.attr, 69 &memmap_type_attr.attr, 70 NULL 71 }; 72 73 static const struct sysfs_ops memmap_attr_ops = { 74 .show = memmap_attr_show, 75 }; 76 77 /* Firmware memory map entries. */ 78 static LIST_HEAD(map_entries); 79 static DEFINE_SPINLOCK(map_entries_lock); 80 81 /* 82 * For memory hotplug, there is no way to free memory map entries allocated 83 * by boot mem after the system is up. So when we hot-remove memory whose 84 * map entry is allocated by bootmem, we need to remember the storage and 85 * reuse it when the memory is hot-added again. 86 */ 87 static LIST_HEAD(map_entries_bootmem); 88 static DEFINE_SPINLOCK(map_entries_bootmem_lock); 89 90 91 static inline struct firmware_map_entry * 92 to_memmap_entry(struct kobject *kobj) 93 { 94 return container_of(kobj, struct firmware_map_entry, kobj); 95 } 96 97 static void __meminit release_firmware_map_entry(struct kobject *kobj) 98 { 99 struct firmware_map_entry *entry = to_memmap_entry(kobj); 100 101 if (PageReserved(virt_to_page(entry))) { 102 /* 103 * Remember the storage allocated by bootmem, and reuse it when 104 * the memory is hot-added again. The entry will be added to 105 * map_entries_bootmem here, and deleted from &map_entries in 106 * firmware_map_remove_entry(). 107 */ 108 spin_lock(&map_entries_bootmem_lock); 109 list_add(&entry->list, &map_entries_bootmem); 110 spin_unlock(&map_entries_bootmem_lock); 111 112 return; 113 } 114 115 kfree(entry); 116 } 117 118 static struct kobj_type __refdata memmap_ktype = { 119 .release = release_firmware_map_entry, 120 .sysfs_ops = &memmap_attr_ops, 121 .default_attrs = def_attrs, 122 }; 123 124 /* 125 * Registration functions ------------------------------------------------------ 126 */ 127 128 /** 129 * firmware_map_add_entry() - Does the real work to add a firmware memmap entry. 130 * @start: Start of the memory range. 131 * @end: End of the memory range (exclusive). 132 * @type: Type of the memory range. 133 * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised 134 * entry. 135 * 136 * Common implementation of firmware_map_add() and firmware_map_add_early() 137 * which expects a pre-allocated struct firmware_map_entry. 138 * 139 * Return: 0 always 140 */ 141 static int firmware_map_add_entry(u64 start, u64 end, 142 const char *type, 143 struct firmware_map_entry *entry) 144 { 145 BUG_ON(start > end); 146 147 entry->start = start; 148 entry->end = end - 1; 149 entry->type = type; 150 INIT_LIST_HEAD(&entry->list); 151 kobject_init(&entry->kobj, &memmap_ktype); 152 153 spin_lock(&map_entries_lock); 154 list_add_tail(&entry->list, &map_entries); 155 spin_unlock(&map_entries_lock); 156 157 return 0; 158 } 159 160 /** 161 * firmware_map_remove_entry() - Does the real work to remove a firmware 162 * memmap entry. 163 * @entry: removed entry. 164 * 165 * The caller must hold map_entries_lock, and release it properly. 166 */ 167 static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) 168 { 169 list_del(&entry->list); 170 } 171 172 /* 173 * Add memmap entry on sysfs 174 */ 175 static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry) 176 { 177 static int map_entries_nr; 178 static struct kset *mmap_kset; 179 180 if (entry->kobj.state_in_sysfs) 181 return -EEXIST; 182 183 if (!mmap_kset) { 184 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj); 185 if (!mmap_kset) 186 return -ENOMEM; 187 } 188 189 entry->kobj.kset = mmap_kset; 190 if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++)) 191 kobject_put(&entry->kobj); 192 193 return 0; 194 } 195 196 /* 197 * Remove memmap entry on sysfs 198 */ 199 static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry) 200 { 201 kobject_put(&entry->kobj); 202 } 203 204 /** 205 * firmware_map_find_entry_in_list() - Search memmap entry in a given list. 206 * @start: Start of the memory range. 207 * @end: End of the memory range (exclusive). 208 * @type: Type of the memory range. 209 * @list: In which to find the entry. 210 * 211 * This function is to find the memmap entey of a given memory range in a 212 * given list. The caller must hold map_entries_lock, and must not release 213 * the lock until the processing of the returned entry has completed. 214 * 215 * Return: Pointer to the entry to be found on success, or NULL on failure. 216 */ 217 static struct firmware_map_entry * __meminit 218 firmware_map_find_entry_in_list(u64 start, u64 end, const char *type, 219 struct list_head *list) 220 { 221 struct firmware_map_entry *entry; 222 223 list_for_each_entry(entry, list, list) 224 if ((entry->start == start) && (entry->end == end) && 225 (!strcmp(entry->type, type))) { 226 return entry; 227 } 228 229 return NULL; 230 } 231 232 /** 233 * firmware_map_find_entry() - Search memmap entry in map_entries. 234 * @start: Start of the memory range. 235 * @end: End of the memory range (exclusive). 236 * @type: Type of the memory range. 237 * 238 * This function is to find the memmap entey of a given memory range. 239 * The caller must hold map_entries_lock, and must not release the lock 240 * until the processing of the returned entry has completed. 241 * 242 * Return: Pointer to the entry to be found on success, or NULL on failure. 243 */ 244 static struct firmware_map_entry * __meminit 245 firmware_map_find_entry(u64 start, u64 end, const char *type) 246 { 247 return firmware_map_find_entry_in_list(start, end, type, &map_entries); 248 } 249 250 /** 251 * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem. 252 * @start: Start of the memory range. 253 * @end: End of the memory range (exclusive). 254 * @type: Type of the memory range. 255 * 256 * This function is similar to firmware_map_find_entry except that it find the 257 * given entry in map_entries_bootmem. 258 * 259 * Return: Pointer to the entry to be found on success, or NULL on failure. 260 */ 261 static struct firmware_map_entry * __meminit 262 firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type) 263 { 264 return firmware_map_find_entry_in_list(start, end, type, 265 &map_entries_bootmem); 266 } 267 268 /** 269 * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do 270 * memory hotplug. 271 * @start: Start of the memory range. 272 * @end: End of the memory range (exclusive) 273 * @type: Type of the memory range. 274 * 275 * Adds a firmware mapping entry. This function is for memory hotplug, it is 276 * similar to function firmware_map_add_early(). The only difference is that 277 * it will create the syfs entry dynamically. 278 * 279 * Return: 0 on success, or -ENOMEM if no memory could be allocated. 280 */ 281 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type) 282 { 283 struct firmware_map_entry *entry; 284 285 entry = firmware_map_find_entry(start, end - 1, type); 286 if (entry) 287 return 0; 288 289 entry = firmware_map_find_entry_bootmem(start, end - 1, type); 290 if (!entry) { 291 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC); 292 if (!entry) 293 return -ENOMEM; 294 } else { 295 /* Reuse storage allocated by bootmem. */ 296 spin_lock(&map_entries_bootmem_lock); 297 list_del(&entry->list); 298 spin_unlock(&map_entries_bootmem_lock); 299 300 memset(entry, 0, sizeof(*entry)); 301 } 302 303 firmware_map_add_entry(start, end, type, entry); 304 /* create the memmap entry */ 305 add_sysfs_fw_map_entry(entry); 306 307 return 0; 308 } 309 310 /** 311 * firmware_map_add_early() - Adds a firmware mapping entry. 312 * @start: Start of the memory range. 313 * @end: End of the memory range. 314 * @type: Type of the memory range. 315 * 316 * Adds a firmware mapping entry. This function uses the bootmem allocator 317 * for memory allocation. 318 * 319 * That function must be called before late_initcall. 320 * 321 * Return: 0 on success, or -ENOMEM if no memory could be allocated. 322 */ 323 int __init firmware_map_add_early(u64 start, u64 end, const char *type) 324 { 325 struct firmware_map_entry *entry; 326 327 entry = memblock_alloc(sizeof(struct firmware_map_entry), 328 SMP_CACHE_BYTES); 329 if (WARN_ON(!entry)) 330 return -ENOMEM; 331 332 return firmware_map_add_entry(start, end, type, entry); 333 } 334 335 /** 336 * firmware_map_remove() - remove a firmware mapping entry 337 * @start: Start of the memory range. 338 * @end: End of the memory range. 339 * @type: Type of the memory range. 340 * 341 * removes a firmware mapping entry. 342 * 343 * Return: 0 on success, or -EINVAL if no entry. 344 */ 345 int __meminit firmware_map_remove(u64 start, u64 end, const char *type) 346 { 347 struct firmware_map_entry *entry; 348 349 spin_lock(&map_entries_lock); 350 entry = firmware_map_find_entry(start, end - 1, type); 351 if (!entry) { 352 spin_unlock(&map_entries_lock); 353 return -EINVAL; 354 } 355 356 firmware_map_remove_entry(entry); 357 spin_unlock(&map_entries_lock); 358 359 /* remove the memmap entry */ 360 remove_sysfs_fw_map_entry(entry); 361 362 return 0; 363 } 364 365 /* 366 * Sysfs functions ------------------------------------------------------------- 367 */ 368 369 static ssize_t start_show(struct firmware_map_entry *entry, char *buf) 370 { 371 return snprintf(buf, PAGE_SIZE, "0x%llx\n", 372 (unsigned long long)entry->start); 373 } 374 375 static ssize_t end_show(struct firmware_map_entry *entry, char *buf) 376 { 377 return snprintf(buf, PAGE_SIZE, "0x%llx\n", 378 (unsigned long long)entry->end); 379 } 380 381 static ssize_t type_show(struct firmware_map_entry *entry, char *buf) 382 { 383 return snprintf(buf, PAGE_SIZE, "%s\n", entry->type); 384 } 385 386 static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr) 387 { 388 return container_of(attr, struct memmap_attribute, attr); 389 } 390 391 static ssize_t memmap_attr_show(struct kobject *kobj, 392 struct attribute *attr, char *buf) 393 { 394 struct firmware_map_entry *entry = to_memmap_entry(kobj); 395 struct memmap_attribute *memmap_attr = to_memmap_attr(attr); 396 397 return memmap_attr->show(entry, buf); 398 } 399 400 /* 401 * Initialises stuff and adds the entries in the map_entries list to 402 * sysfs. Important is that firmware_map_add() and firmware_map_add_early() 403 * must be called before late_initcall. That's just because that function 404 * is called as late_initcall() function, which means that if you call 405 * firmware_map_add() or firmware_map_add_early() afterwards, the entries 406 * are not added to sysfs. 407 */ 408 static int __init firmware_memmap_init(void) 409 { 410 struct firmware_map_entry *entry; 411 412 list_for_each_entry(entry, &map_entries, list) 413 add_sysfs_fw_map_entry(entry); 414 415 return 0; 416 } 417 late_initcall(firmware_memmap_init); 418 419